Deformographic target assembly with integral conductive member

ABSTRACT

The conductive member associated with the target assembly of a deformographic display system is affixed to one side of the deformable dielectric member of the target assembly. The opposite side of the deformable dielectric member is affixed to the relatively non-deformable dielectric member, which is part of the target assembly and which stores the electrostatic charge pattern containing the information to be displayed. The conductive member is deformable and compatibly deforms with the deformable dielectric member in response to the deformations of the latter. The deformations of the dielectric member in turn are produced by the forces of the electrostatic field which results between the conductive member and the electron charge pattern. By affixing the conductive member to the deformable dielectric member, the deformations occur substantially in the same or one direction, i.e., in a direction towards the non-deformable dielectric member.

United States Patent [451 July 11, 1972 Kozol et al.

[54] DEFORMOGRAPHIC TARGET ASSEMBLY WITH INTEGRAL CONDUCTIVE MEMBER [72] Inventors: Eugene T. Kozol, Binghamton, N.Y.;

Robert J. Wohl, San Jose, Calif.

[73] Assignee: International Business Machines Corporation, Armonk, NY.

[22] Filed: Oct. 29, 1970 [21] Appl. No.: 85,187

[52] U.S.Cl. ..178/7.5D,3l3/9l,350/161 [51] Int. Cl ....H04n 5/66, l-IOlj 29/12, G02f1/28 [58] FieldofSearch ..3l3/89,9l; l78/5.4 BD, 7.3 D,

[56] References Cited UNITED STATES PATENTS 2,896,507 7/1959 Mast et a1. ..l78/7.5 D

3,158,430 11/1964 McNaney ....350/16l 3,238,296 3/1966 Nelson et al ..350/l6l WRITE GUN 18 Hi 3,001,447 9/1961 Ploke ..3l3/9l Primary Examiner-Robert L. Griffin Assistant Examiner-George G. Stellar Attorney-Hanifin & Jancin and Norman R. Bardales [5 7] ABSTRACT The conductive member associated with the target assembly of a deformographic display system is affixed to one side of the deformable dielectric member of the target assembly. The 0pposite side of the deformable dielectric member is afiixed to the relatively non-defonnable dielectric member, which is part of the target assembly and which stores the electrostatic charge pattern containing the information to be displayed. The conductive member is deformable and compatibly deforms with the defonnable dielectric member in response to the deformations of the latter. The deformations of the dielectric member in turn are produced by the forces of the electrostatic field which results between the conductive member and the electron charge pattern. By afiixing the conductive member to the deformable dielectric member, the deformations occur substantially in the same or one direction, i.e., in a direction towards the non-deformable dielectric member.

7 Claims, 5 Drawing Figures DEFORMOGRAPHIC TARGET ASSEMBLY WITH INTEGRAL CONDUCTIVE MEMBER CROSS-REFERENCE TO RELATED APPLICATIONS Application, Ser. No. 683,292, filed Nov. 15, 1967 entitled Deformographic Storage Display Tube", Robert J. Wohl, coinventor herein, Frank A. Hawn, and Harold C. Medley, now abandoned in lieu of co-pending continuation application Ser. No. 48,862, filed June 12, 1970 now (1.5. Pat. No. 3,626,084, and assigned to the common assignee herein, describes a deformographic storage display tube utilizing a target assembly with a spaced electrode or conductive member as hereinafter explained.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a target assembly for deformographic display systems and the like.

2. Description of the Prior Art Heretofore in certain prior art deformographic display systems of the type utilizing a target assembly having as a part thereof an electrostatically deformable dielectric member, it was the practice to space the conductive member, which was at some given reference potential such as ground and which was associated with the target assembly, apart from the deformable dielectric member.

One such system, for example, is described in the aforementioned co-pending application. Briefly, in that system the target assembly is located in an evacuated display tube. The conductive member is placed as a transparent film on the inside surface of the tubes face plate. The target assembly is spaced away from the conductive member with its deformable dielectric member positioned to face the face plate, and its nondeformable dielectric member facing a pair of electron guns located in the rear of the tube. One gun is used for writing, i.e., placing the electron charge pattern on the non-deformable dielectric member, and the other for erasing the pattern.

A deformation responsive optical system is utilized in conjunction with the tube to translate the deformations of the deformable member into a visible image. The particular optical system described in the aforementioned co-pending application is of the schlieren type, and the co-pending application describes both transmissive and reflective type systems. In the transmissive system, the light provided by the optical system is passed through the transparent tube face and conductive member. It then passes in sequence through vacuum, and then the deformable and non-deformable dielectric members of the target assembly, which are affixed to each other and are generally transparent or translucent in nature. The light passing through the deformable member is refracted and diffracted by the deformations of the deformable member and hence is modulated by the information contained in the electron charge pattern stored in the non-deformable member. The light is then passed through an exit window of the tube which, for the transmissive type optical system, is provided for this purpose. Upon exiting from the window, the light is picked up by the receiving end of the optical system and translated to the visible image.

In the reflective system, the target assembly is modified so as to provide a dielectric mirror which is sandwiched between the assemblys deformable and non-deformable members. As a result, after the light passes in sequence through the series of elements, which includes the transparent tube face and conductive member, vacuum and transparent deformable member, it is reflected back by the mirror through the same mentioned elements but in reverse sequence. The receiving portion of the optical system is positioned to intercept the light as it exits from the face plate of the tube and in turn translates it to the visible image. Further details as to the description and operation of the deformographic display tube and its attendant optical system may be found in the aforementioned co-pending application, incorporated herein by reference.

While the aforedescribed target assembly and spaced conductive member or reference electrode was found to be generally satisfactory for many applications, it was found to have certain disadvantages. For one, its resolution capability was somewhat limited. Moreover, the deformations of the deformable member were bi-directional, i.e., both inward and outward, and for a complex electron charge pattern, were somewhat difficult to control and/or maintain. The bidirectional deformations also caused a depth-of-focus problem which further adversely affected the resolution of the system. Another disadvantage in the case of the reflective target assembly is that an additional member, i.e., the dielectric mirror, was required to be introduced into the system and thereby increased its complexity both structurally and as hereinafter explained electrostatically as well. The dielectric mirror is also expensive and difficult to fabricate.

SUMMARY OF THE INVENTION t is an object of this invention to provide a target assembly and conductive member combination in a deformographic display system with an improved resolution and sensitivity.

Another object of this invention is to provide a simple and compact target assembly and conductive member combination in a deformographic display system.

Still another object of this invention is to provide the aforementioned target assembly and conductive member combination for use with a deformographic display tube and its attendant optics.

As part of our invention, we have discovered that the problem with the aforedescribed prior art target assembly and spaced conductive member configuration is due to two an tagonistic forces which cause the deformographic dielectric member to deform in two different directions as now will be explained.

In the deformographic system of the type related to the present invention the deformable dielectric member is such a good insulator that it may be considered to have no free charges per se which are utilized to provide the deformation forces. In the deformographic type systems, the free charges of the electron charge pattern and their conjugate or opposite polarity image charges are located on the non-deformable dielectric member and conductive member, respectively. In the spaced conductive member and target assembly configuration, the non-homogeneous dielectric media between the charge pattern and the conductive medium and/or nonhomogeneous electrostatic field cause unbalanced transitory forces to be present which, in turn, causes the deformable member to deform. As a result, for the last mentioned configuration, the deformations take place in two opposite directions, extremities of which are related to the respective classical point charge and uniform charge situations or cases, i.e., high and low spatial frequency of the charge pattern, respectively.

In the point charge case, such as, for example, is the situation where the charged area on the surface of the nondeforrnable member is small compared to the distance to the conductive member, the electrostatic field lines will rapidly diverge from the charge area toward the conductive member. Thus, there is produced a gradient in the field intensity. Accordingly, the positive pole of a dipole of the deformable dielectric member, which is nearest the electron charge on the nondeforrnable dielectric member, experiences an attractive force. The repulsive force on the negative pole of the dipole will be less, resulting in a net attractive force tending to depress the deformable member inwardly, i.e., in a direction toward the electron charge. The pressure increase dp caused by this force, which is equilibrated by the elastic restoring force built up on the deformable members by the deformation, may be shown to be:

where s permittivity of free space,

K, relative dielectric content of the deformable dielectric member, and

E electric field intensity.

When the charged area is large compared to the distance to the conductive member, i.e., low spatial frequency, the field lines extend straight and parallel and a uniform field apparently exists. However, even here a force is developed, due to the fact that the electric flux density or electric displacement vector D ends only on free charges, while the electrostatic field intensity vector E can terminate either g1 free or bound, i.e., polarization charges. Thus, the vector D extends unchanged through the several media, to wit: the nondeformable and deformable dielectric members, the vacuous space and to the conductive member, where it terminates on the free image charges. The vector E, on the other hand, will vary through these media in such a manner as to keep the vector D constant. This is expressed in the well-known relationship:

(2) where K dielectric constant, and

e, permittivity of free space.

Thus, just outside the surface of the deformable member, the field intensity E in the vacuum is:

where K, the relative dielectric constant of the vacuum. Inside the deformable dielectric member, the field intensity E is:

1 1 o); where K the relative dielectric constant of the deformable member.

Therefore:

r/ o (5) Since K, K,,, then E, E or the field intensity just outside the deformable member is greater than that inside it. Thus, over a small laminar portion of the deformable member surface which fac s the conductive member, the field vector increases from E to E Since dipoles in an electrostatic field gradient are forced in the direction of increasing field strength, this force is directed up from the surface, so as to cause an elevation or thickening of the film. The differential in pressure, or force per unit area, is shown in equation l Thus, two antagonistic forces have been described, one the point charge case causing surface depression of the deformable member, and the uniform charge case causing elevation of its surface. For complex electron charge patterns, the net force operative will be a function of the difference. The magnitude of this difference will be dependent upon the spatial frequency of the stored electrostatic charge pattern, for a given reference or ground-plane spacing.

In accordance with the principles of our invention, to improve the recording sensitivity of the deformable dielectric member, one case is favored over the other, thereby increasing the differential. More particularly, the solution of the present invention is that the conductive member be placed directly on the surface of the deformable dielectric member. The conductive member is compatibly deformable with the deformable dielectric member. In transmissive systems, it is transparent; and in reflective systems, it is reflective thereby eliminating the requirement for the dielectric mirror and thus further simplifying the electrostatics. As a result, all the deformations take place in one direction, i.e., inwardly towards the electron charge pattern for both the uniform and point charge cases and hence any other more complex charge pattern.

The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of the preferred embodiments of the invention, as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective schematic view, partly broken away, of a deformographic display system, which is of the tube and transmissive type, utilizing an embodiment of the target assembly of the present invention;

canon FIG. 2 is a cross-sectional partial view of the target assembly of the present invention used in the display system shown in FIG. ll;

FIG. 3 is a cross-sectional partial view of the target assembly of the transmissive type deformographic display tube system described in the aforementioned co-pending application;

FIG. 4 is a perspective schematic view, partly broken away, of a deformographic display system, which is of the tube and reflective type, utilizing another embodiment of the target assembly of the present invention; and

FIG. 5 is a partial perspective view of another display system utilizing another deformographic assembly embodiment of the present invention.

In the figures, like elements are designated with similar reference numerals.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is preferably utilized in deformographic display systems of the tube type. In FIG. 1, tube 10 of such a system is illustrated.

Tube 10 is an evacuated sealed type made of glass or any other suitable material and is provided with a suitable geometry. It has a transparent face plate 11, and an enlarged cylindrical-like hollow portion 12. Appended to the latter are hollow on-axis and off-axis neck portions 13 and 14, respectively. Another neck portion 15 is terminated in an optically clear or transparent window 16. An annular channel or flangelike configuration 17 is provided at the front end of portion 12.

Neck portion 13 houses the electron gun 18, which includes schematically shown cathode, grid, pre-accelerating anode, and focusing electrodes 19-22, respectively. In addition, the gun 18 also includes a final accelerating anode electrode coating 23 which is provided on the inner wall of tube 10 in a conventional manner. Electron gun I8 is used for writing the electron charge pattern, and a suitable beam deflection system such as an electromagnetic type, for example, utilizing deflection yoke 24 disposed about neck 13, is provided for deflecting the beam.

An appropriate bias supply, shown schematically as battery 25, is connected between the cathode electrode 19 and grid electrode 20 via a signal source 26. In the absence of an input signal to the terminal 27 of source 26, which may be of the video information type, the gun 18 is biased at cut-off. In the presence of an information signal at terminal 27, the gun 18 is turned on and the intensity of the resultant electron beam is modulated by the information signal in a conventional manner. Other bias supplies, shown schematically as batteries 28, 29 and 30, provide the pre-acceleration, focusing and final acceleration reference voltages between the cathode electrode 18 and the pre-acceleration anode, focusing, and final acceleration anode electrodes 21, 22 and 23, respectively, electrode 23 being grounded at 31 as shown in FIG. 1.

An erase gun 32, which is of the flood-type, has its cathode, control grid and accelerating anode electrodes 33, 34 and 35, respectively, housed in neck portion 14. Accelerating anode 35 is connected commonly to electrode 23, which collectively form the accelerating anode system for erase gun 32. An appropriate bias supply, not shown, which is part of the erase control circuit 36 maintains gun 32 in an off condition in the absence of a control signal at the input terminal 37. In the presence of such a control signal at terminal 37, gun 32 provides a flood beam which erases the previously written electron charge pattern.

Tube 10 is associated with an appropriate attendant deformation responsive optical system and for which the given embodiment of FIG. 1 is of the transmissive type. By way of example, the optical system may be of the schlieren type and identical to the transmissive optical system described in the aforementioned application. For sake of clarity, the optical system is shown in block form as two boxes 38, 39 designated by the respective legends OPTICS (I) and OPTICS (II), respectively.

Housed in the flange-like portion 17 is an embodiment of the target assembly and conductive member combination of the present invention, generally indicated by the reference numeral 40 and shown in greater detail in FIG. 2. It comprises a relatively non-deformable extended dielectric substrate 41 such as mica, for example, that is a generally planar or sheetlike member. It faces the gun side of the tube and is used to store the electron charge pattern. Its outer periphery is mounted to the inner wall of flange portion 17 in an appropriate sealed fashion, such as by peripheral seals and joinders, not shown. Mounted directly on the surface of member 41 which is remote from the gun side is a deformable dielectric member 42 in the form of a film or layer, referred to herein sometimes as a deformographic film.

The deformographic film 42 for the embodiment of FIG. 1 may generally comprise any highly translucent or substantially transparent dielectric solid type material depending upon factors such as resolution and contrast. The film should deform rapidly in response to stresses, the time of deformation being determined by the viscosity of the material used for the film. Upon removal of the charge, the film relaxes to a plane state principally due to the surface tension forces and the elastic modulus of the material. The writing, development and display are substantially simultaneous, the development and relaxation times being determined by the properties of the material used for the film. Polymeric media are generally preferred because of the longer storage times provided, faster erasure, high resolution, and no orientation limitations. Preferably, film materials which yield excellent results for practically all applications of the invention are silicone polymers. Judiciously selected ones of these polymers have high optical transparency, high electrical resistivity, and high compliance. The imaginary or viscous component of the complex elastic modulus of such material is reasonably low, providing good results, such as fast transient response, for example. Two such silicone polymers particularly suitable for this use are available in their uncured states and referred to by the manufacturer as XR-63-493 and Sylgard 51.

In accordancewith the principles of the present invention, a compatible deformable conductive member 43 is mounted directly, e.g., by an evaporation process, onto the other surface of the deformable dielectric member 42. When used with a transmissive optical system, such as is the case for the display system of FIG. 1, the conductive member is transparent and may be made of any suitable material. It preferably is made of gold, particularly when it is to be used with the aforementioned silicone polymer type members 42. Alternatively, aluminum may be used. As previously explained, with the target assembly configuration of the present invention, deformation of the deformable member 42, and consequently member 43, take place in one direction which is inwardly toward the electron charge pattern stored by member 41.

For sake of comparison, there is shown in FIG. 2 idealized point and uniform charge distribution patterns 44 and 45, respectively, which are stored by member 41, and their respective resultant inward deformations 46 and 47. By way of reference, dash line 48 represents the vertical left edge profile of the target 40, when its deformable members 42, 43 are in a relaxed condition, i.e., there is no charge pattern stored by member 41.

Further, by way of comparison, there is shown in FIG. 3, the transmissive target assembly and spaced conductive member configuration 40A described and utilized in the aforementioned application. Briefly, as previously explained, it comprised a dielectric storage member 41A which had one side that faced the gun side of the tube in which it was mounted, and a deformable dielectric member 42A which is affixed to the other side of member 41A. The conductive member 43A was located on the inner surface of the tubes face plate 11A and spaced from the deformable member 42A. For the reasons previously explained, deformations of member 42A occurred in both directions, i.e., inwardly and outwardly, as typified by the respective deformations 46A and 47A associated with the idealized point and uniform charge patterns 44A and 45A shown in FIG. 3. By way of reference, dash line 48A represents the vertical left edge profile of the target member 42A when it is in a relaxed condition, i.e., there is no charge pattern stored by member 41A.

The target assembly of the present invention is capable of storing 250 optical line pairs per inch or greater. In some cases, as high as 325 optical line pairs per inch have been obtained. Moreover, the increased line density was provided without raster breakup or degradation. For example, the target assembly of the present invention is capable of having a storage time of 30 minutes with only a 10 percent degradation in brightness of the viewed image. Of course, in a cyclic system where the electron charge pattern is periodically rewritten on the target assembly with alternate erasure cycles by judiciously selecting the frame frequency, substantially no gradation is obtained. The member 41 may be made of optical mica and if desired to enhance further the micas storage property, its surface which faces the electron gun side of the tube may be coated with an insulating layer of a very highly resistive material such as silicon monoxide, silicon dioxide, magnesium oxide or magnesium fluoride, by, for example, an evaporation process.

The principles of operation of deformographic display tubes is well known and will not be set forth in great detail herein. Briefly, however, when it is desired to write an electron charge pattern on the member 41 of FIG. 1, the information desired to be displayed is provided as input signals at terminal 27 whereupon source 26 provides control signals to grid electrode 21 which modulate the intensity of the electron beam provided by gun 18 in response to the input signals at terminal 27. In synchronization therewith, deflection circuitry 24A provides deflection signals to yoke 24 which deflects the beam across the target member 41 in a predetermined raster, e. g., a horizontal scan pattern of the TV type. As a result, at the end of the frame, an electron charge distribution pattern is stored by the member 41. If desired, the electron charge distribution pattern may be periodically refreshed by cyclically repeating the modulating and scanning operation of the write beam of gun 18.

As is well known, the write gun is operated at sufiicient energy levels to provide accelerating voltages which establish a secondary emission ratio less than unity at the dielectric member 41, resulting in the electron charge distribution pattern being stored thereby. An electrostatic field results between the electron charge pattern and the conductive member 43, which is at some predetermined reference potential such as ground shown schematically at 49, c.f. FIG. 1, resulting in a deformographic pattern in the deformable member 42, and in the member 43. As aforementioned, the deformations take place in one direction toward the charge pattern and are related to the charge distribution pattern and hence the information contained in the signals at terminal 27.

To translate the deformation pattern into a visible image, light from the portion 38 of the deformation-responsive optical system 38-39 is transmitted in sequence through the face plate 11, target assembly 40 where it is diffracted and refracted in response to the deformations thereof, and from there it passes out the window 16. Portion 39 intercepts the exiting light and projects the image onto a viewing screen for viewing purposes and/or onto a photosensitive recording member.

To erase the electron charge pattern, the flood electron gun is operated at sufficient energy levels to provide accelerating voltages which establish a secondary emission ratio greater than unity at the member 41. As a result, the electron gun erases the previously stored charge pattern.

In FIG. 4, there is shown a deforographic display system of the sealed tube type which utilizes a deformation-responsive optical system 50 which is of the reflective type and which, for example, may be identical to the schlieren reflective type optical system described in the aforementioned co-pending application. Appropriate electronics and biasing means are provided with the tube but are omitted in FIG. 4 for sake of clarity and may be similar to those utilized in FIG. 1.

The configuration of the embodiment of the target assembly 40' shown in FIG. 4 is identical to that of target assembly 40 of FIG. 1, except that the conductive member 43' is preferably made of silver for its reflective optical properties. Alternatively, aluminum may be utilized. The light from system 50 is reflected by member 43 back into optics system 50 where it is translated into a visible image.

It should be understood that while the invention has been described in a sealed tube system, that it may also be used in a demountable tube. It should be further understood that while the invention is described as being preferably utilized in an evacuated system, this is mainly because of the means, i.e., an electron beam, utilized for providing the electron charge distribution pattern and the resulting electrostatic field produced thereby to deform the deformable member 42 of 42' as the case may be. Thus, other means for providing an electron charge distribution pattern may be provided either in a nonevacuated or evacuated system.

For example, as shown by the embodiment of FIG. 5, the deformographic assembly 51 may comprise a deformable dielectric solid type member 52, a matrix of deformable conductive members 53 afiixed to one of its surfaces, e.g., by evaporation, and a supporting substrate 54 such as mica or glass affixed to its other surface. Carried by or embedded in the substrate 54 is another matrix of conductors 55. By selectively energizing the conductors 53 and 55, a localized inward deformation between an upper and lower conductor so energized will occur in the deformable dielectric member 52 and hence a predetermined deformation pattern may be produced therein. As is obvious, this may be accomplished in or out of a vacuum.

The embodiment of FIG. 5 shows by way of example a two dimensional XY array. As is apparent to those skilled in the art, a one dimensional array may also be provided by eliminating one of the groups of conductors, i.e., the group of conductors 53 or the group of conductors 55, and in lieu thereof providing an integral or continuous conductive coating. Of course, if the conductors 53 are selected to be eliminated, then the continuous conductive coating would likewise have compatible deformable characteristics to those of the member 52. Other conductor array patterns, such as, for example, radial or alpha-numeric patterns, may be employed as is apparent to those skilled in the art. In addition, the display assembly 51 may be modified so that the lower conductors 55 are carried directly by the deformable member 52 such as by an evaporation process and/or embedded in the member 52. In the assembly 51 and the aforedescribed modifications, the conductive members 53 and/or 55 would be made transparent and/or reflective depending on whether the assembly was to be used with a transmissive or reflective type deformation-responsive optical system and the direction in which the incoming light would be incident thereto.

It should be further understood that while the invention has been described in the tube system employing two individual guns for write and erase purposes, that the tube and its attendant electronics may be modified so as to require only one gun for providing both these purposes in a manner apparent to those skilled in the art.

Thus, while the invention has been particularly shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that the foregoing and other changes in form and detail may be made therein without departing from the spirit and scope of the invention.

We claim:

1. In a deformographic display system of the type having a deformable solid dielectric first member means having a side in contacting relationship with an electrostatically chargeable nonconductive second member means and means for charging said second member means with a predetermined charge pattern, the improvement com rising:

conductlve compatibly eformable third member means in a predetermined contacting and joining relationship with an opposite side of said first member means, said first member means being deformed in a unidirectional manner whenever said second member means has an electron charge pattern stored thereon, and said third member means being likewise deformed in said unidirectional manner.

2. A deformographic display system according to claim I wherein said conductive third member means is transparent.

3. A deformographic display system according to claim 1 wherein said conductive third member means is optically reflective.

4. A deformographic display system according to claim 1 wherein said first, second and third member means are disposed in an evacuated environment.

5. A deformographic display system according to claim 1 wherein said deformable dielectric first member means is a silicone polymer and said conductive third member means is gold.

6. A deforrnographic display system according to claim 1 wherein said deformable dielectric first member means is a silicone polymer and said conductive third member means is silver.

7. A deformographic display system according to claim 1 wherein said first, second and third member means are mounted in an evacuated tube, and said means for charging said second member comprises an electron gun apparatus mounted in said tube. 

1. In a deformographic display system of the type having a deformable solid dielectric first member means having a side in contacting relationship with an electrostatically chargeable nonconductive second member means and means for charging said second member means with a predetermined charge pattern, the improvement comprising: conductive compatibly deformable third member means in a predetermined contacting and joining relationship with an opposite side of said first member means, said first member means being deformed in a unidirectional manner whenever said second member means has an electron charge pattern stored thereon, and said third member means being likewise deformed in said unidirectional manner.
 2. A deformographic display system according to claim 1 wherein said conductive third member means is transparent.
 3. A deformographic display system according to claim 1 wherein said conductive third member means is optically reflective.
 4. A deformographic display system according to claim 1 wherein said first, second and third member means are disposed in an evacuated environment.
 5. A deformographic display system according to claim 1 wherein said deformable dielectric first member means is a silicone polymer and said conductive third member means is gold.
 6. A deformographic display system according to claim 1 wherein said deformable dielectric first member means is a silicone polymer and said conductive third member means is silver.
 7. A deformographic display system according to claim 1 wherein said first, second and third member means are mounted in an evacuated tube, and said means for charging said second member comprises an electron gun apparatus mounted in said tube. 